Signatures of Long-Range Spin-Triplet Component in Andreev Interferometer

Anatoly F. Volkov

doi:10.1103/PhysRevB.102.094517

paper

Signatures of Long-Range Spin-Triplet Component in Andreev Interferometer

arXiv:2007.02757 · doi:10.1103/PhysRevB.102.094517

Abstract

We analyze the Josephson, $I_{J}$ , and dissipative, $I_{V}$ , currents in a magnetic Andreev interferometer in the presence of the long-range spin triplet component (LRSTC). Andreev interferometer has a cross-like geometry and consists of a SF $_{l}$ - F - F $_{r}$ S circuit and perpendicular to it a N - F - N circuit, where S, F $_{l, r}$ are superconductors and weak ferromagnets with non-collinear magnetisations $M_{l, r}$ , F is a strong ferromagnet with a high exchange energy. The ferromagnetic wire F can be replaced with a non-magnetic wire n. In the limit of a weak proximity effect (PE), we obtain simple analytical expressions for the currents $I_{J}$ and $I_{V}$ . In particular, the critical Josephson current in a long Josephson junction (JJ) is $I_{c} (α, β) = I_{0 c} χ (α, β)$ , where the function is a function of angles $(α, β)_{l, r}$ that characterize the orientations of $M_{l, r}$ . The oscillating part of the dissipative current $I_{osc} (V) = χ (α, β) cos φ I_{0} (V)$ in the N - F(n)- N circuit depends on the angles $(α, β)_{l, r}$ in the same way as the critical Josephson current $I_{c} (α, β)$ , but can be much greater than the $I_{c} (α, β)$ . At some angles the current $I_{c} (α, β)$ changes sign. We briefly discuss a relation between the negative current $I_{c}$ and paramagnetic response. We argue that the measurements of the conductance in N - F(n) - N circuit can be used as another complementary method to identify the LRSTC in S/F heterostructures.

15 pages, 6 figures. Final version, some formulas are corrected

Signatures of Long-Range Spin-Triplet Component in Andreev Interferometer

Abstract

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